Mulch door with sensor

ABSTRACT

A mower includes a cutting deck supporting a cutting blade having a fixed blade sail and a door having a first position in which the door covers an opening through which grass clippings can pass, and a second position in which the door does not cover the opening. The mower also has a switch configured to send a mode signal indicating that the door is in the first position or the second position. The mower also has a controller configured to receive the mode signal and adjust the cutting blade to rotate at a first speed when the mode signal indicates that the door is in the first position, and a second speed when the mode signal indicates that the door is in the second position. The mower also includes an electric battery to power rotation of the cutting blade.

This application claims the benefit of U.S. Provisional Application No.62/831,502, filed Apr. 9, 2019, the contents of which are hereinincorporated by reference.

BACKGROUND

Walk-behind rotary mowers for cutting grass use a rotating blade to clipgrass as a user pushes the mower along the grass. Rotary mowers have ablade that is powered by a motor and a cutting deck that houses theblade. The geometry of the cutting deck and the cutting blade, as wellas the speed of the blade, affect how grass is cut and how it isconveyed within the cutting deck.

Grass clippings can be disposed of in a number of ways that includedischarging, bagging and mulching. When discharging, grass clippings areejected from the cutting deck onto the surrounding area without beingcollected. When bagging grass clippings, the clippings are ejected fromthe cutting deck and conveyed into a collection bag through a chute inthe mower deck. Alternatively, clippings can be mulched by cutting thegrass clippings into very small pieces by circulating the clippingsinside the cutting deck. These small pieces then fall down between theblades of grass, where the clippings can decompose.

Mowers exist that can switch between bagging and mulching. Because theclippings are physically transported differently when bagging ordischarging than when mulching—downward toward the ground in the case ofmulching, and out of the cutting deck when bagging—a configuration thatis optimal for one mode may not be optimal for the other mode.

SUMMARY

One general aspect includes a cutting deck supporting a cutting bladethat is rotatable around a substantially vertical axis, the cuttingblade having a fixed blade sail. The cutting deck also includes anopening in the cutting deck through which grass clippings can pass. Thecutting deck also includes a collection bag configured to receive grassclippings that pass through the opening in the cutting deck. The cuttingdeck also includes a door having a first position in which the doorcovers the opening, and a second position in which the door does notcover the opening. The cutting deck also includes a switch configured tosend a mode signal indicating that the door is in the first position orthe second position. The cutting deck also includes a trip affixed tothe mower, the trip configured such that a change in door positioncauses the trip to be sensed by the switch. The cutting deck alsoincludes a controller configured to receive the mode signal and adjustthe cutting blade to rotate at a first speed when the mode signalindicates that the door is in the first position, and a second speedwhen the mode signal indicates that the door is in the second position.The cutting deck also includes an electric battery operable to powerrotation of the cutting blade at the first speed and at the secondspeed.

Implementations may include one or more of the following features. Themower where the cutting blade has a medium blade sail height of 1.5 inch(38 mm) or less. The mower where the first speed is lower than thesecond speed. The mower where the first speed is between about 2200 and2400 rotations per minute, and the second speed is between about 2600and 2800 rotations per minute. The mower where the second speed is amaximum speed of the mower. The mower where the first speed is avariable speed that varies within a speed range, where the second speedis higher than the speed range of the first speed, and where thecontroller is further configured to step up blade speed to the secondspeed in response to receiving the mode signal indicating that the dooris in the second position. The mower where the mower is configured suchthat attaching the collection bag to the mower causes the trip to besensed by the switch. The mower where the collection bag is removablyattachable to the mower, and where a position of the door is independentof whether the collection bag is attached to the mower.

One general aspect includes a mower including: a cutting deck supportinga cutting blade that is rotatable around a substantially vertical axis,the cutting blade having a fixed blade sail; an opening in the cuttingdeck through which grass clippings can pass; a collection bag configuredto receive grass clippings that pass through the opening in the cuttingdeck; a door adjacent to the opening, the door having a first positionin which the door covers the opening, and a second position in which thedoor does not cover the opening; a handle configured to move the doorbetween the first position and the second position; a switch configuredto send a mode signal indicating that the door is in the first positionor the second position; a controller configured to receive the modesignal and adjust the cutting blade to rotate at a first speed when themode signal indicates that the door is in the first position, and asecond speed when the mode signal indicates that the door is in thesecond position; and an electric battery operable to power rotation ofthe cutting blade at the first speed and at the second speed.

Implementations may include one or more of the following features. Themower where the handle and the door are an integrally formed unit. Themower where the switch is configured to be tripped by rotation of theintegrally formed unit around a substantially horizontal axis. The mowerfurther including a trip that triggers the switch to send the modesignal. The mower where the switch is a Hall effect sensor.

One general aspect includes a mower including: a cutting deck supportinga cutting blade that is rotatable around a substantially vertical axis,the cutting blade having a fixed blade sail; a motor controlling thecutting blade to operate at one of a first rate of speed and a secondrate of speed; an electric battery configured to power the motor; anopening in the cutting deck through which grass clippings can pass; acollection bag configured to receive grass clippings that pass throughthe opening in the cutting deck; a door pivotably attached to thecutting deck, the door having a first configuration in which the doorobstructs the opening and a second configuration in which the door doesnot obstruct the opening; a sensor fixedly attached to the mower, thesensor configured to send a mode signal based on a configuration of thedoor; and a controller configured to receive the mode signal andinstruct the motor to operate the cutting blade at the first rate ofspeed or the second rate of speed based on the mode signal.

Implementations may include one or more of the following features. Themower where the door rests on top of the collection bag when thecollection bag is attached to the mower and when the door is in thesecond configuration. The mower where the sensor is a Hall effectsensor. The mower where the first configuration corresponds to a mulchmode and the second configuration corresponds to a bagging mode. Themower further including a trip configured to trigger the sensor to sendthe mode signal. The mower where the trip is fixedly attached to thedoor. The mower where the sensor is a Hall effect sensor and the trip isa magnet.

This summary is an overview of some of the teachings of the presentapplication and is not intended to be an exclusive or exhaustivetreatment of the present subject matter. Further details are found inthe detailed description and appended claims. Other aspects will beapparent to persons skilled in the art upon reading and understandingthe following detailed description and viewing the drawings that form apart thereof, each of which is not to be taken in a limiting sense. Thescope herein is defined by the appended claims and their legalequivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first mower according to someexamples.

FIG. 2 is a perspective view of the mower of FIG. 1 according to someexamples.

FIG. 3 is a cutaway view of the mower of FIG. 1 showing a mulch door ofthe first mower according to some examples.

FIG. 4 is a cutaway view of the mower of FIG. 1 showing the mulch doorof FIG. 3 according to some examples.

FIG. 5 is a rear view of the mower of FIG. 1 according to some examples.

FIG. 6 is a bottom view of the mower of FIG. 1 according to someexamples

FIG. 7 is a perspective view of a second mower according to analternative example.

FIG. 8 is a rear view of the mower of FIG. 7 according to some examples.

FIG. 9 is a rear view of a mulch door of the second mower according tosome examples.

FIG. 10 is a bottom view of the mower of FIG. 7 according to someexamples.

FIG. 11 is a schematic view of a control system for a mower according tosome examples.

FIG. 12A is an isometric perspective view of a mower blade according tosome examples.

FIG. 12B is a front elevational view of the mower blade of FIG. 12A.

FIG. 12C is a side elevational view of the mower blade of FIG. 12A.

FIG. 13A is an isometric perspective view of a mower blade according tosome examples.

FIG. 13B is a front elevational view of the mower blade of FIG. 13A.

FIG. 13C is a side elevational view of the mower blade of FIG. 13A.

While embodiments are susceptible to various modifications andalternative forms, specifics thereof have been shown by way of exampleand drawings, and will be described in detail. It should be understood,however, that the scope herein is not limited to the particular aspectsdescribed. On the contrary, the intention is to cover modifications,equivalents, and alternatives falling within the spirit and scopeherein.

DETAILED DESCRIPTION

The technology described herein is appropriate for use with abattery-operated mower. Gasoline-powered engines typically include fuelreservoirs that hold more than enough fuel to power the engine for longperiods of time. Therefore, power conservation is generally not asignificant concern. In contrast, battery-powered engines are morelimited in their energy storage capacity. A battery-powered mowergenerally has a shorter run time before there is a need to recharge thebattery.

One of the factors affecting the amount of power drawn from the batteryis engine speed, which translates to the speed of the cutting blade. Ahigher blade speed draws more power than a low blade speed. A lowerblade speed can be appropriate when operating in mulch mode, in whichgrass clippings are recirculated through the cutting deck of the moweruntil they are cut into small enough pieces to be driven into theground. A lower blade speed is less appropriate for bagging mode, wherethe grass clippings need to be ejected from the cutting deck. When theblade speed is too low, grass clippings are not efficiently propelledout of the cutting deck and into the collection bag. Increasing thespeed of the cutting blade during bagging mode improves baggingperformance.

Various examples of the disclosed technology provide a walk-behindrotary mower that is capable of automatically changing the speed of thecutting blade based on whether a mulch door is open or closed. If themulch door is closed, the cutting blade rotates at a first speed. If themulch door is open, the cutting blade rotates at a second, higher speed.The first configuration is a mulch mode in which the mulch door isclosed and the cutting blade operates at a first speed. The secondconfiguration is a bagging mode in which the mulch door is open and thecutting blade operates at a higher speed. By using a lower speed inmulch mode, power is conserved and mowing time is extended. By using ahigher speed when the grass clippings need to be ejected from thecutting deck in bagging mode, better performance is provided.

The cutting blade speed is controlled by a central controller. Thecontroller receives a mode signal indicating that the mulch door isopened, and adjusts the speed of the engine in response to the modesignal to operate at the higher speed. In some examples, a sensor orswitch attached to the mower detects whether the mulch door is open orclosed. The words “sensor” and “switch” can be used interchangeably tomean a mechanism that receives an input and generates an output. Theswitch can be mechanical or electrical. In some examples, the switch isfixedly attached to the mower. The switch can be attached to the mulchdoor, or the switch can be attached to the body of the mower.

In some examples, the system further includes a trip, separate from theswitch, that is configured to activate the switch. In some examples, theswitch and the trip are attached to two different parts of the mower,and relative motion of the trip with respect to the switch causes theswitch to sense the trip. The trip can be attached to the mower or tothe mulch door. The trip can be attached to the mulch door while theswitch is attached to the mower near the mulch door. This arrangementallows electrical wiring to the switch located on the mower and avoidsthe complication of wiring to a moveable mulch door, in situations wherethe trip does not require wiring. It is also possible for the switch tobe attached to the mulch door while the trip is attached to the mowernear the mulch door. It is also possible for the switch and trip to beattached to other parts of the mower besides the mulch door and near themulch door.

Control and Power System for a Mower

FIG. 11 is a schematic view of a control system for a mower according tosome examples. The system 1101 includes a control unit 1115 thatcoordinates operation of the system 1101. A motor 1125 drives a cuttingblade 1135 which has a sharpened cutting edge. Options for driving theblade include directly by an output shaft from the motor, a hydraulicmotor, or through a belt and pulley system to a blade hub. The motor1125 is capable of driving the cutting blade 1135 at different desiredspeeds. The control unit 1115 is configured to receive a mode signalfrom a switch 1145 that indicates whether a mulch mode or a bagging modeis required. In response to the mode signal, the control unit 1115 setsthe cutting blade 1135 speed to the desired speed. In some examples, thesystem 1101 is powered by a battery 1175. The battery 1175 is arechargeable electric battery in some examples. The battery 1175 can bea single- or multiple-cell battery pack, such as a lithium ion batterypack.

A mulch door 1150 is moveable between a first position 1152 and a secondposition 1154. The mulch door includes a trip 1160 configured toactivate the switch 1145 to indicate whether the mulch door is closed oropen. If the mulch door is closed and the mower is in a mulching mode,the cutting blade rotates at a first speed. If the mulch door is openand the mower is in a bagging mode, then the cutting blade rotates at asecond, higher speed. By using a lower speed in mulch mode, power isconserved and mowing time is extended. By using a higher speed when thegrass clippings need to be ejected from the cutting deck in baggingmode, better bagging performance is provided.

Examples of mowers with this type of control arrangement are describedherein. Any of the mowers and control arrangements described herein mayalso be used with gas-powered mowers having a gas motor, resulting infuel being conserved in the mulching mode and the time between refillinga gas tank being extended.

Mower of FIG. 1-6

Now referring to FIGS. 1-6, mower 101 is one example of a mower capableof automatically switching between a first speed when a mulch door isclosed and a second, higher speed when a mulch door is open. Mower 101has a cutting deck 112 supporting and enclosing the rotating cuttingblade. Mower 101 further has a rear housing 114 attached to a rear sideof the cutting deck 112. Mower 101 is supported by a plurality of wheels109. The mower 101 is powered by an electric, rechargeable batteryhoused within the engine housing 122. The mower 101 can be propelled bya rear wheel drive, a front wheel drive, or an all-wheel drive.

A collection bag 131 is configured to receive grass clippings through anopening in the cutting deck 112. In some examples, the collection bag131 is removeable, and can be easily attached to and detached from themower 101. A mulch door handle 151 is provided to switch theconfiguration of the mower 101 from a bagging mode to a mulching mode.FIG. 1 shows the mulch door handle 151 in a lowered orientationcorresponding to a bagging mode in which grass clippings are conveyedfrom the cutting deck 112 through an opening in the cutting deck andinto the collection bag 131. In FIG. 2, the mulch door handle 151 is inan upright orientation corresponding to a mulch mode, in which grassclippings are circulated within the cutting deck 112 and chopped into afine mulch that falls toward the ground. The handle 151 is graspable bythe user to move between a mulch mode and a bagging mode. A mode label203 is included in some examples to indicate to the user which mode isselected and includes indicia, such as words, symbols, representations,or drawings, to convey each mode. For example, the mode label 203includes a recycling symbol to indicate the mulching mode and arepresentation of a collection bag on a mower to indicate the baggingmode.

FIG. 3 is a cutaway view of the mower 101 in the mulch configuration,where a portion of rear housing 114 is cut away to provide a view of themulch door 311 connected to the mulch door handle 151. In the example ofFIG. 3, the mower 101 can be put into mulch mode or bagging mode basedon the configuration of a mode switch unit 301. The mode switch unit 301includes an door 311 and a lever arm 321 attached to the door 311 by ashaft 331. The mode switch unit 301 is configured to rotate around anaxis of the shaft 331. In some examples, the axis of the shaft 331 issubstantially horizontal. In some examples, the door 311, lever arm 321,and shaft 331 are integrally formed. An opening in the cutting deck 112leads to a discharge passage 351. The discharge passage 351 is definedby the rear assembly 114. In bagging mode, grass clippings are allowedto exit the cutting deck 112 through the passage 351 and into thecollection bag 131.

FIG. 5 shows a rear view of the mower 101. The discharge passage 351leads from the opening in the cutting deck to a rear housing opening601. In the view of FIG. 5, the door 311 is in a first closed position,blocking the opening from the cutting deck and into the dischargepassage 351. The view of FIG. 5, therefore, shows the mower 101 in mulchmode. In bagging mode, the door 311 would be in a second open position,with the mode switch unit oriented upward to unblock the opening in thecutting deck leading to the passage 351, allowing grass clippings toexit the opening in the cutting deck 112, enter the discharge passage351, and enter the collection bag 131.

A rear door 510 is visible in FIG. 5, in an open position uncovering therear housing opening 601. The rear door 510 is also visible in FIG. 1.The rear door 510 can rotate between a closed position covering the rearhousing opening (not shown) and the open position shown in FIG. 5. Insome examples, the rear door 510 is spring-biased into the closedposition. In some examples, the rear door 510 has a width in the samedirection as its axis of rotation of at least about 10 inches (25 cm),at most about 20 inches (51 cm), or about 15 inches (38 cm). In someexamples, the rear door 510 has a length in a direction extending awayfrom and perpendicular to its axis of rotation of at least about 6inches (15 cm), at most about 10 inches (25 cm), or about 8 inches (20cm).

The mode switch unit 301 can be made of a hard polymer, such as HDPE(high density polyethylene). The mode switch unit 301 is attached to therear housing 114, such as to a wall of the discharge passage 351. Insome examples, the shaft 331 can be seated in brackets on the top of therear housing 114. In other examples, the mode switch unit 301 can beattached to the cutting deck 112. In some examples, the shaft 331 can beseated in brackets on the top of the cutting deck 112. The shaft 331 isrotatable around an axis. The door handle 151 is controlled by a user byapplying force on the lever arm 321. The force on the lever arm 321causes rotation of the shaft 331, and rotation of the door 311 inside ofthe passage 351. When the door handle 151 is in an upright orientation(as in FIG. 1), the mower is in a mulching mode and the door 311 of themode switch unit 301 is in a first position blocking the opening throughthe cutting deck, preventing grass clippings from exiting the cuttingdeck 112 and entering the passage 351. When the door handle 151 is in alowered orientation (as in FIG. 2), the door 311 is in a second positionthat does not block the opening in the cutting deck. FIG. 4 is a cutawayview of the mower 101 similar to FIG. 3 except the mode switch unit 301is in the bagging configuration. In this configuration, grass clippingscan be propelled through the passage 351 into the collection bag 131.

The physical orientation of the mode switch unit 301 determines whetherthe mower 101 is in bagging mode or mulching mode. When the lever arm321 of the door handle 151 is raised, the door 311 is lowered and blocksthe opening to the passage 351, causing the mower 101 to operate inmulch mode. When the lever arm 321 of the door handle 151 is lowered,the door 311 is raised and no longer blocks the opening to the passage351, causing the mower 101 to operate in bagging mode. The door 311 islocated at the end of the passage 351 closest to the cutting blade,blocking the opening from the cutting deck 112. The door 311 has asubstantially rectangular shape corresponding to the shape of theopening in the cutting deck. A thickness of the door 311 is much lessthan its width or length, such as about 25% or less, as the door servesto block the opening to the cutting deck but does not need to occupy thepassage 351.

The door 311 can be constructed using a waffle structure as shown inFIGS. 3-4 to increase the strength and decrease the weight. In someexamples, the door 311 has a width in the same direction as the shaft331 of at least about 4 inches (10 centimeters (cm)), at least about 5inches (13 cm), at least about 6 inches (15 cm), at least about 7 inches(18 cm), at least about 8 inches (20 cm), at most about 10 inches (25cm), at most about 9 inches (23 cm), and at most about 8 inches (20 cm).In some examples, the door 311 has a width of at least about 6 inches(15 cm) and at most about 9 inches (23 cm).

In some examples, the door 311 has a length in a direction extendingaway from and perpendicular to the shaft 331 of at least about 5 inches(13 cm), at least about 6 inches (15 cm), at least about 7 inches (18cm), at least about 8 inches (20 cm), at least about 9 inches (23 cm),at least about 10 inches (25 cm), at most about 9 inches (23 cm), and atmost about 10 inches (25 cm), at most about 11 inches (28 cm). In someexamples, the door 311 has a length of at least about 8 inches (20 cm)and at most about 10 inches (25 cm).

Referring now to FIGS. 1 and 3, only the handle 151 and a portion of thelever arm 321 of the mode switch unit 301 are visible from a top, sideor front view of the mower 101 above the rear housing 114. The remainderof the mode switch unit 301, including a lower part of the lever arm321, the shaft 331 and the mulch door 311, are hidden under the rearhousing 114.

FIG. 3 shows the mulch door 311 in a closed position and the collectionbag 131 attached to the mower 101. The mower 101 can be convenientlyswitched between the mulching mode and the bagging mode independently ofwhether the collection bag 131 is attached using the handle 151, so thata user does not need to remove the collection bag in order to switchfrom a bagging mode to a mulching mode and thereby saves steps.

A switch 371 is provided to sense the orientation of the mode switchunit 301, and a trip 361 is provided to cause switching of the switch371 to indicate which mode is being used. In the example of FIGS. 3-4,the switch 371 is fixedly attached to the cutting deck 112, and the trip361 is fixedly attached to the moveable mode switch unit 301. Inparticular, the trip 361 is attached to the rotatable shaft 331. Whenthe lever arm 321 is rotated around the horizontal axis of the shaft331, the trip 361 also rotates around the horizontal axis, resulting ina change in distance between the trip 361 and the switch 371. The switch371 senses this change in the relative position of the trip 361 andinterprets the change as a mode signal to change from bagging mode tomulch mode or vice versa.

In one example, the switch 371 is a Hall effect sensor and the trip 361is a magnet. In this example, the magnet is sensed by the Hall effectsensor. As discussed in relation to FIG. 11, a mode signal from theswitch 371 is sent to a control unit to indicate the change from baggingmode to mulch mode or vice versa.

In an alternative embodiment, a trip is located on the lever arm 321 andthe switch is near a first position of the lever arm 321 or a secondposition of the lever arm 321.

In use, the mower 101 can be switched from mulch mode to bagging mode asfollows. Starting with the door handle 151 in an upright orientation asshown in FIG. 3, the trip 361 is in a first position at a first distancefrom the switch 371. A user applies torque to the lever arm 321 to causethe mode switch unit 301 to rotate around the horizontal axis of theshaft 331. This in turn causes the door 311 to swing upward, allowingthe opening of the cutting deck 112 to be unblocked, as demonstrated inFIG. 4. Switch 371 remains stationary as the mode switch unit 301 isconverted from mulch mode to bagging mode. The trip 361 rotates aroundthe horizontal axis along with the lever arm 321, moving into a secondposition at a second distance from the switch 371, where the seconddistance is smaller than the first distance. The switch 371 detects thechange in position of the trip 361 and generates a mode signalindicating the change. The mode signal is sent to a controller,described in relation to FIG. 11. There are many different options forthe detection and control scheme that are further described herein.

FIG. 6 shows a bottom view of the mower 101. This view shows the cuttingdeck 112 supporting a cutting blade 614 that is rotatable around asubstantially vertical axis, represented by axis 615. In some examples,the cutting blade has a fixed blade sail, which are described inrelation to FIGS. 12-13. A wall 621 of the cutting deck 112 defines aninterior cavity 625 that houses the cutting blade 614. The dischargepassage 351 leads from an opening 601 in the cutting deck 112 to theopening 501 in the rear housing 114. When the mode switch unit 301 is inthe mulch configuration, clippings do not leave the interior cavity 625,and are forced downward into the ground. When the mode switch unit 301is in the bagging configuration, grass clippings are thrown from theinterior cavity 625 through the opening 601, into the passage 351, andinto a collection bag 131.

Mower of FIGS. 7-10

In an alternative example of a mower according to some examples shown inFIGS. 7-10, a mower is capable of switching between a mulch mode and abagging or discharge mode and automatically adjusting between a firstspeed when a mulch door is closed and a second, higher speed when amulch door is open. In FIG. 7, a mower 701 includes a cutting deck 721and a motor housing 703 to house a motor for the mower 701. The cuttingdeck 721 surrounds the rotating cutting blade and is attached to a rearhousing 725. Wheels support the mower. The mower 101 can be propelled bya front wheel drive, a rear wheel drive, or an all-wheel drive.

The mower 701 includes a removable collection bag 731. The mower 701includes a mulch door 741 in an open position so that grass clippingscan enter the collection bag 731. The mulch door 741 is visible from thetop, front, and side views of the mower 701 when the mower is in abagging mode. FIG. 8 is a rear view of the mower 701 in which the mower701 is configured for mulch mode with a mulch door 741 closed andwithout the collection bag 731. The mulch door 741 is visible from therear view when the mower is in a bagging mode. The mulch door is notcovered by the rear housing 725.

FIG. 9 is a rear view of the mower 701 in which the mower 701 isconfigured for bagging, with the mulch door 741 open. In the view ofFIG. 9, the collection bag is not present in order to facilitateexplanation of the system. However, during use in bagging mode, thecollection bag 731 would be attached to the rear of the mower, as seenin FIG. 7.

Turning now to FIGS. 8-9, the mower 701 can be converted between mulchmode and bagging mode by changing the orientation of a mulch door 741that includes a door flap 742 and a mulch plug 943. The mulch plug 943is integral with the mulch door 741. The mulch plug 943 is sized to fitwithin an passage 951 that leads from an interior of the cutting deck721 to a rear housing opening 953. The mulch door 741 is rotatablearound a substantially horizontal axis defined by a shaft 811.

FIG. 8 shows the mower 701 in mulch mode, in which the mulch door 741covers the passage 951. In mulch mode, the mulch plug 943 sits withinthe passage 951, blocking any grass clippings from leaving the interiorcavity of the cutting deck 721. FIG. 9 shows the mower 701 in baggingmode, in which the mulch door 741 does not cover the passage 951.Converting the mower 701 from mulch mode to bagging mode involves thestep of removing the mulch plug 943 from the passage 951 by lifting thedoor flap 742, causing the mulch door 741 to rotate around thesubstantially horizontal axis defined by shaft 811.

In some examples, the mulch door 741 has a width in the same directionas its axis of rotation of at least about 10 inches (25 cm), at mostabout 20 inches (51 cm), or about 14 inches (36 cm). In some examples,the mulch door 741 has a length in a direction extending away from andperpendicular to its axis of rotation of at least about 6 inches (15cm), at most about 10 inches (25 cm), or about 8 inches (20 cm).

The mulch plug 943 of the mulch door 741 can be constructed using awaffle structure as shown in FIG. 9 to increase the strength anddecrease the weight. In some examples, the mulch plug 943 has a width inthe same direction as the shaft 811 of at least about 4 inches (10centimeters (cm)), at least about 5 inches (13 cm), at least about 6inches (15 cm), at least about 7 inches (18 cm), at least about 8 inches(20 cm), at most about 10 inches (25 cm), at most about 9 inches (23cm), and at most about 8 inches (20 cm). In some examples, the mulchplug 943 has a width of at least about 6 inches (15 cm) and at mostabout 9 inches (23 cm).

In some examples, the mulch plug 943 has a length in a directionextending away from and perpendicular to the shaft 811 of at least about5 inches (13 cm), at least about 6 inches (15 cm), at least about 7inches (18 cm), at least about 8 inches (20 cm), at least about 9 inches(23 cm), at least about 10 inches (25 cm), at most about 9 inches (23cm), and at most about 10 inches (25 cm), at most about 11 inches (28cm). In some examples, the mulch plug 943 has a length of at least about8 inches (20 cm) and at most about 10 inches (25 cm).

Now referring to FIG. 9, the mulch door 741 is attached to an exteriorsurface of the rear housing 725. The attachment location of the mulchdoor 741 is near the rear housing opening 953, which is at the end ofthe passage 951 furthest from the cutting blade. The mulch door 741 isnot attached to the cutting deck 721.

A switch 871 is attached to the mower. In the example of FIG. 8, theswitch 871 is fixedly attached to one side of the mower. Other locationsfor the switch are possible, however. A trip 861 is attached to themower. In the example of FIG. 8, the trip 861 is fixedly attached to thedoor flap 742, but other locations are possible. In the embodiment shownin FIGS. 8-9, the trip 861 is located on the underside surface of thedoor flap 742 visible in FIG. 9. The trip may alternatively be locatedon the outside surface of the door flap 742 visible in FIG. 8 or can beembedded in the material of the door flap 742. The switch 871 and trip861 are positioned such that when the door flap 742 is in the mulchconfiguration seen in FIG. 8, the switch 871 and the trip 861 are in afirst position, spaced apart by a first distance. When the door flap 742is in a bagging or discharge configuration, seen in FIG. 9, the switch871 and the trip 861 are in a second position, spaced apart by a seconddistance less than the first distance. The switch can detect the changein position of the trip from the first position to the second position.In the example of the figures, lifting the door flap 742 to convert themulch door from mulch mode to bagging mode causes the trip 861 to movebetween the first position at the first distance from the switch 871 tothe second position at the second distance from the switch 871. In someexamples, the switch 871 is a Hall effect sensor, and the trip 861 is amagnet.

In use, the mower 701 can be switched from mulch mode to bagging mode asfollows. Starting with the mulch door 741 in the mulch doorconfiguration in FIG. 8, the door flap 742 is lifted upward, whichreveals the passage 951. The magnet of the trip 861 approaches the Halleffect sensor of the switch 871, allowing the magnet to be detected bythe Hall effect sensor. The sensor then sends a mode signal to acontroller to indicate that the bagging mode is desired.

In the example of FIGS. 8-9, the switch 871 remains stationary and thetrip 861 moves with the mulch door 741 as the mower 701 is convertedfrom mulch mode to bagging mode. This arrangement allows electricalwiring to the switch 871 located on the mower and avoids thecomplication of wiring to the moveable mulch door 741, as the trip doesnot require wiring. In alternative configurations, the trip 861 could bestationary and the switch 871 could be attached to a moving part such asthe mulch door 741.

FIG. 10 shows a bottom view of the mower 701. This view shows thecutting deck 721 supporting a cutting blade 1014 that is rotatablearound a substantially vertical axis, represented by axis 1015. In someexamples, the cutting blade has a fixed blade sail, which are describedin relation to FIGS. 12-13. A wall 1021 of the cutting deck 721 definesan interior cavity 1025 that houses the cutting blade 1014. An opening1001 in the cutting deck 721 leads from the interior cavity 1025 to thepassage 951 (not shown) defined by the passage housing 1051. When themulch door 741 is in the mulch configuration, clippings do not leave theinterior cavity 1025, and are circulated inside of the interior cavity1025 and ultimately forced downward into the ground. When the mulch door741 is open, grass clippings are thrown from the interior cavity 1025through the opening 1001 and passage housing 1051 and deposited into acollection bag in bagging mode.

The plug 943 portion of the mulch door is visible in FIG. 10 closing offthe opening 1001 to the passage housing 1051. The plug 943 occupies thepassage 951 when the mulch door is closed. The presence of the plug 943prevents air from swirling in the passage 951 when the mower is in themulching mode, so that the airflow is more conducive to causing theblades of grass to stand straighter for cutting.

Switch and Trip Options

There are many options for a switch or a switch and a trip for use inthe mower embodiments described herein. The output of the switchindicates to the controller if the trip is in a first position or asecond position. In any of the examples described herein, the switch canbe a Hall effect sensor and the trip can be a magnet. In these examples,the switch provides an output voltage proportional to the magnetic fieldstrength through it. In one example, when the trip is in the secondposition, the switch outputs a voltage and when the trip is in the firstposition, the switch does not output a voltage. The output of the switchis used to determine whether the mulch door is open, when voltage isoutput by the switch, or closed, when no voltage is output by theswitch.

In another example for a Hall effect sensor, when the trip is in thesecond position, the switch outputs a first voltage and when the trip isin the first position, the switch outputs a second, lower voltage. Theoutput of the switch is used to determine whether the mulch door isopen, when a voltage over a threshold voltage is output by the switch,or closed, when a voltage below a threshold voltage is output by theswitch.

In some examples, the switch is an electronic switch that can beoperated rapidly by a movement. In some examples, the switch is amomentary switch which is only engaged while it is in an activatedposition and is otherwise normally in an inactivated position. In someexamples, the switch is a pressure switch or a magnetic switch.

These are just a few examples of the possible switch and switch and triparrangements and control schemes.

Cutting Blade Speed Settings

In various examples, the motor of the mower can drive the cutting bladeat different speeds based on the configuration of the mower. The cuttingblade can have a first mulch mode speed in a mulching mode and anincreased second bagging speed, higher than the first mulch mode speed,when the mulch door is open.

In some examples, the cutting blade can also have a variable range ofspeeds appropriate for different mowing conditions, such as wet grass ordry grass. A lower blade speed that is appropriate for dry, sparse turfmay not efficiently cut heavy or wet turf because dry, sparse turfprovides less resistance than turf that is heavy, wet, or both. Themulch mode speed in this example is variable based on turf condition. Insome examples, the controller varies the cutting blade speed based onlow or high resistance mowing conditions in the mulch modeconfiguration, while the bagging mode causes the blade to rotate at amaximum speed regardless of mowing conditions. In some examples, thehigh-resistance mulch mode speed is equal to the bagging speed. In someexamples, both the high-resistance mulch mode speed and the baggingspeed are the maximum, highest speed for the mower.

For example, an exemplary the cutting blade with a length of 21.75inches (55.2 cm) can have variable speeds as measured by rotations perminute (RPM) in the range of 2200 RPM to 2900 RPM. In some examples, thecutting blade can operate at a narrow range of speeds as a stepfunction, with a low speed set at a particular speed and a high speedset at a particular stepped-up speed that is higher than the low speed.For example, a first, lowest speed can corresponding to mulch mode indry and low-resistance conditions.

In one example, the blade can have a lowest speed in the range ofbetween about 2200 and about 2400 RPM, or about 2300 RPM (about 13,000feet per minute for a 21.75 inch blade). At this lowest speed, the runtime of the battery will be maximized when a higher speed is not neededto propel the clippings into the collection bag or deal with a heavierload.

An increased-load speed can correspond to mulch mode in lush, dense, orwet conditions which cause a heavier load. The heavier load on the bladefrom cutting is an input to the controller. In one example, the bladecan have an increased-load speed in the range of between about 2600 andabout 2800 RPM, or about 2700 RPM.

A highest speed can correspond to bagging mode, to have improved baggingof the grass clipping. In one example, the blade can have a highestspeed that is in the range of about 2600 to about 2800 RPM, or about2700 RPM (about 15,000 feet per minute for a 21.75 inch blade). Anaccepted safety limit for tip speed is 19,000 feet per minute (97 meterper second), which correlates to a speed of about 3300 RPM for a bladewith a length of 21.75 inches (55.2 cm). In one embodiment, highestspeed of the mower is about 3300 RPM. In one embodiment, the baggingspeed for the mower is about 3300 RPM.

Cutting Blade Sail

FIGS. 12A-C and 13A-C show two examples of a cutting blade for a rotarymower. The sail of a cutting blade is a turned-up area opposite thecutting blade. Both the cutting edge and the sail contribute to thequality-of-cut. The sail is important because it causes air flow thatpulls grass up straight, thereby producing an even cut.

FIGS. 12A-C show a blade 1200 with a high sail, while FIGS. 13A-C show ablade 1300 with a medium sail. Blade 1200 includes a sharpened cuttingedge 1202 and a blade sail area 1204. Blade 1300 includes a sharpenedcutting edge 1302 and a blade sail area 1304. Blade 1200, blade 1300,and many different options for cutting blade configurations can be usedwith any of the examples described herein.

Fixed Blade Sail

Both cutting blade 1200 and cutting blade 1300 have a fixed blade sail.Mowers having cutting blades with moveable flaps in the blade sail areaare known in the prior art. In contrast, a blade with a fixed blade saildoes not have moveable parts in the blade sail area. In some examples,blade 1200 and blade 1300 are formed from a single piece of material,such as steel.

Medium Blade Sail

In any of the embodiments described herein, one option is to use acutting blade having a medium blade sail. A blade with too little sailwill not generate sufficient air flow to give good bagging performance.A blade with too much sail will perform well at bagging, but will drawexcessive power from the limited resources of a battery powered mower.

The amount of blade sail is determined by the angle of the blade sailand the blade sail area. One aspect of the blade sail is the height asshown by Hf for a full or high blade sail in FIG. 12C and Hm for amedium blade sail in FIG. 13C. In the examples of FIGS. 12C and 13C, thewidth of the blade as measured from side to side in the view of FIGS.12C and 13C is about 2.32 inches (59 millimeters (mm)). In someexamples, Hm of FIG. 13C is at least about 0.5 inch (13 millimeters(mm)), at most about 1 inch (25 mm), at most about 1.5 inch (38 mm), orabout 0.77 inch (20 mm). In contrast, a full blade sail of FIG. 12C isgreater than 1 inch (2.5 cm), or about 1.01 inch (2.5 cm).

Discharge Mode

In some examples, the mower is capable of a discharge mode where grassis discharged from the cutting deck but is not bagged. Mower 101 shownin FIG. 1 includes a side discharge door 160. Mower 701 shown in FIG. 8also includes a side discharge door 860. To operate in discharge modeusing the side discharge opening, the mulch door will be in a closedposition and the side discharge door will be open. A side dischargechute (not shown) may be attached to the side discharge door to directthe grass clippings. In one example, the default speed of the mower willbe a first, lower speed when the discharge mode is used. In thisexample, the closed position of the mulch door indicates either adischarge mode or a mulching mode and the mower operates at a first,lower speed in both the discharge mode or in the mulching mode.

In other examples, mower 101 or mower 701 may be provided without a sidedischarge door. A discharge mode may still be provided by arear-attaching discharge chute (not shown) that can attach to the rearof the mower in place of the collection bag. In some examples, therear-attached discharge chute is shaped to direct grass clippings towarda side of the mower. In this example, the mulch door will be open in thedischarge mode. As a result, the system will run at a second, higherspeed in the discharge mode and in the bagging mode.

It should be noted that, as used in this specification and the appendedclaims, the singular forms “a,” “an,” and “the” include plural referentsunless the content clearly dictates otherwise. It should also be notedthat the term “or” is generally employed in its sense including “and/or”unless the context clearly dictates otherwise.

It should also be noted that, as used in this specification and theappended claims, the phrase “configured” describes a system, apparatus,or other structure that is constructed or configured to perform aparticular task or adopt a particular configuration. The phrase“configured” can be used interchangeably with other similar phrases suchas arranged and configured, constructed and arranged, constructed,manufactured and arranged, and the like.

All publications and patent applications in this specification areindicative of the level of ordinary skill in the art to which thisinvention pertains. All publications and patent applications are hereinincorporated by reference to the same extent as if each individualpublication or patent application was specifically and individuallyindicated by reference.

As used herein, the recitation of numerical ranges by endpoints shallinclude all numbers subsumed within that range (e.g., 2 to 8 includes2.1, 2.8, 5.3, 7, etc.).

The headings used herein are provided for consistency with suggestionsunder 37 CFR 1.77 or otherwise to provide organizational cues. Theseheadings shall not be viewed to limit or characterize the invention(s)set out in any claims that may issue from this disclosure. As anexample, although the headings refer to a “Field,” such claims shouldnot be limited by the language chosen under this heading to describe theso-called technical field. Further, a description of a technology in the“Background” is not an admission that technology is prior art to anyinvention(s) in this disclosure. Neither is the “Summary” to beconsidered as a characterization of the invention(s) set forth in issuedclaims.

The embodiments described herein are not intended to be exhaustive or tolimit the invention to the precise forms disclosed in the followingdetailed description. Rather, the embodiments are chosen and describedso that others skilled in the art can appreciate and understand theprinciples and practices. As such, aspects have been described withreference to various specific and preferred embodiments and techniques.However, it should be understood that many variations and modificationsmay be made while remaining within the spirit and scope herein.

1. A mower comprising: a cutting deck supporting a cutting blade that is rotatable around a substantially vertical axis, the cutting blade having a fixed blade sail; an opening in the cutting deck through which grass clippings can pass; a collection bag configured to receive grass clippings that pass through the opening in the cutting deck; a door having a first position in which the door covers the opening, and a second position in which the door does not cover the opening; a switch configured to send a mode signal indicating that the door is in the first position or the second position; a trip affixed to the mower, the trip configured such that a change in door position causes the trip to be sensed by the switch; a controller configured to receive the mode signal and adjust the cutting blade to rotate at a first speed when the mode signal indicates that the door is in the first position, and a second speed when the mode signal indicates that the door is in the second position; and an electric battery operable to power rotation of the cutting blade at the first speed and at the second speed.
 2. The mower of claim 1, wherein the cutting blade has a medium blade sail height of 1.5 inch (38 mm) or less.
 3. The mower of claim 1, wherein the first speed is lower than the second speed.
 4. The mower of claim 1, wherein the first speed is between about 2200 and 2400 rotations per minute, and the second speed is between about 2600 and 2800 rotations per minute.
 5. The mower of claim 1, wherein the second speed is a maximum speed of the mower.
 6. The mower of claim 1, wherein the first speed is a variable speed that varies within a speed range, wherein the second speed is higher than the speed range of the first speed, and wherein the controller is further configured to step up blade speed to the second speed in response to receiving the mode signal indicating that the door is in the second position.
 7. The mower of claim 1, wherein the mower is configured such that attaching the collection bag to the mower causes the trip to be sensed by the switch.
 8. The mower of claim 1, wherein the collection bag is removably attachable to the mower, and wherein a position of the door is independent of whether the collection bag is attached to the mower.
 9. A mower comprising: a cutting deck supporting a cutting blade that is rotatable around a substantially vertical axis, the cutting blade having a fixed blade sail; an opening in the cutting deck through which grass clippings can pass; a collection bag configured to receive grass clippings that pass through the opening in the cutting deck; a door adjacent to the opening, the door having a first position in which the door covers the opening, and a second position in which the door does not cover the opening; a handle configured to move the door between the first position and the second position; a switch configured to send a mode signal indicating that the door is in the first position or the second position; a controller configured to receive the mode signal and adjust the cutting blade to rotate at a first speed when the mode signal indicates that the door is in the first position, and a second speed when the mode signal indicates that the door is in the second position; and an electric battery operable to power rotation of the cutting blade at the first speed and at the second speed.
 10. The mower of claim 9, wherein the handle and the door are an integrally formed unit.
 11. The mower of claim 10, wherein the switch is configured to be tripped by rotation of the integrally formed unit around a substantially horizontal axis.
 12. The mower of claim 9, further comprising a trip that triggers the switch to send the mode signal.
 13. The mower of claim 9, wherein the switch is a Hall effect sensor.
 14. A mower comprising: a cutting deck supporting a cutting blade that is rotatable around a substantially vertical axis, the cutting blade having a fixed blade sail; a motor controlling the cutting blade to operate at one of a first rate of speed and a second rate of speed; an electric battery configured to power the motor; an opening in the cutting deck through which grass clippings can pass; a collection bag configured to receive grass clippings that pass through the opening in the cutting deck; a door pivotably attached to the cutting deck, the door having a first configuration in which the door obstructs the opening and a second configuration in which the door does not obstruct the opening; a sensor fixedly attached to the mower, the sensor configured to send a mode signal based on a configuration of the door; and a controller configured to receive the mode signal and instruct the motor to operate the cutting blade at the first rate of speed or the second rate of speed based on the mode signal.
 15. The mower of claim 14, wherein the door rests on top of the collection bag when the collection bag is attached to the mower and when the door is in the second configuration.
 16. The mower of claim 14, wherein the sensor is a Hall effect sensor.
 17. The mower of claim 14, wherein the first configuration corresponds to a mulch mode and the second configuration corresponds to a bagging mode.
 18. The mower of claim 14, further comprising a trip configured to trigger the sensor to send the mode signal.
 19. The mower of claim 18, wherein the trip is fixedly attached to the door.
 20. The mower of claim 18, wherein the sensor is a Hall effect sensor and the trip is a magnet. 